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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase;
import java.io.Serializable;
import java.nio.ByteBuffer;
import java.util.Comparator;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.yetus.audience.InterfaceStability;
/**
* Comparator for comparing cells and has some specialized methods that allows comparing individual
* cell components like row, family, qualifier and timestamp
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface CellComparator extends Comparator| , Serializable {
/**
* A comparator for ordering cells in user-space tables. Useful when writing cells in sorted order
* as necessary for bulk import (i.e. via MapReduce).
*
* CAUTION: This comparator may provide inaccurate ordering for cells from system tables, and
* should not be relied upon in that case.
*/
// For internal use, see CellComparatorImpl utility methods.
static CellComparator getInstance() {
return CellComparatorImpl.COMPARATOR;
}
/**
* Lexographically compares two cells. The key part of the cell is taken for comparison which
* includes row, family, qualifier, timestamp and type
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
@Override
int compare(Cell leftCell, Cell rightCell);
/**
* Compare cells.
* @param ignoreSequenceid True if we are to compare the key portion only and ignore the
* sequenceid. Set to false to compare key and consider sequenceid.
* @return 0 if equal, -1 if a < b, and +1 if a > b.
*/
int compare(Cell leftCell, Cell rightCell, boolean ignoreSequenceid);
/**
* Lexographically compares the rows of two cells.
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
int compareRows(Cell leftCell, Cell rightCell);
/**
* Compares the row part of the cell with a simple plain byte[] like the stopRow in Scan.
* @param cell the cell
* @param bytes the byte[] representing the row to be compared with
* @param offset the offset of the byte[]
* @param length the length of the byte[]
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
int compareRows(Cell cell, byte[] bytes, int offset, int length);
/**
* Compares two row bytes
* @param leftRow the byte array of the left row
* @param rightRow the byte array of the right row
* @return greater than 0 if leftRow is bigger, less than 0 if rightRow is bigger, 0 if both rows
* are equal
*/
default int compareRows(byte[] leftRow, byte[] rightRow) {
return Bytes.compareTo(leftRow, rightRow);
}
/**
* @param row ByteBuffer that wraps a row; will read from current position and will reading all
* remaining; will not disturb the ByteBuffer internal state.
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
default int compareRows(ByteBuffer row, Cell cell) {
if (cell instanceof ByteBufferExtendedCell) {
return ByteBufferUtils.compareTo(row, row.position(), row.remaining(),
((ByteBufferExtendedCell) cell).getRowByteBuffer(),
((ByteBufferExtendedCell) cell).getRowPosition(), cell.getRowLength());
}
return ByteBufferUtils.compareTo(row, row.position(), row.remaining(), cell.getRowArray(),
cell.getRowOffset(), cell.getRowLength());
}
/**
* Lexographically compares the two cells excluding the row part. It compares family, qualifier,
* timestamp and the type
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
int compareWithoutRow(Cell leftCell, Cell rightCell);
/**
* Lexographically compares the families of the two cells
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
int compareFamilies(Cell leftCell, Cell rightCell);
/**
* Lexographically compares the qualifiers of the two cells
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return greater than 0 if leftCell is bigger, less than 0 if rightCell is bigger, 0 if both
* cells are equal
*/
int compareQualifiers(Cell leftCell, Cell rightCell);
/**
* Compares cell's timestamps in DESCENDING order. The below older timestamps sorting ahead of
* newer timestamps looks wrong but it is intentional. This way, newer timestamps are first found
* when we iterate over a memstore and newer versions are the first we trip over when reading from
* a store file.
* @param leftCell the left hand side cell
* @param rightCell the right hand side cell
* @return 1 if left's timestamp < right's timestamp -1 if left's timestamp > right's
* timestamp 0 if both timestamps are equal
*/
int compareTimestamps(Cell leftCell, Cell rightCell);
/**
* Compares cell's timestamps in DESCENDING order. The below older timestamps sorting ahead of
* newer timestamps looks wrong but it is intentional. This way, newer timestamps are first found
* when we iterate over a memstore and newer versions are the first we trip over when reading from
* a store file.
* @param leftCellts the left cell's timestamp
* @param rightCellts the right cell's timestamp
* @return 1 if left's timestamp < right's timestamp -1 if left's timestamp > right's
* timestamp 0 if both timestamps are equal
*/
int compareTimestamps(long leftCellts, long rightCellts);
/**
* @return A dumbed-down, fast comparator for hbase2 base-type, the {@link ByteBufferKeyValue}.
* Create an instance when you make a new memstore, when you know only BBKVs will be
* passed. Do not pollute with types other than BBKV if can be helped; the Comparator will
* slow.
*/
Comparator getSimpleComparator();
}
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